6. Search: Games, Minimax, and Alpha-Beta

MIT 6.034 Artificial Intelligence, Fall 2010
Instructor: Patrick Winston

In this lecture, we consider strategies for adversarial games such as chess. We discuss the minimax algorithm, and how alpha-beta pruning improves its efficiency. We then examine progressive deepening, which ensures that some answer is always available.

License: Creative Commons BY-NC-SA

[javi]

Patrick Winston, the professor of this lecture, pass away this July... Thank you Patrick.

[yassinehani]

Minimax : 16:17
alpha beta simple example : 21:51
alpha beta big example : 24:54

[kardsh]

didn't pay attention in my classes, now here i am at 4 am watching a lecture from 7 years

[jRsqILVOY]

The end of this lecture is amazing - covering both the progressive deepening and uneven tree development which is often skipped over.

[BrunoAlmeidaSilveira]

One of the best lectures in the series, fantastic professor and amazing didactic. Many thanks to MIT for this contribution.

[marcossouza]

I'm a Computer Engineering student from Brazil, and thanks to his class, I was finally able to understand the concepts I had been applying in my thesis. One day, I hope to have the honor of studying at MIT.

[johnnybegood]

R.I.P. Patrick Winston, your work will last forever

[sixpooltube]

This is the Breaking Bad of AI lectures. Epic beyond comparison. I've watched it more than once and I've learned something new every time.

[maresfillies]

For those who want to know where he talks about Min Max go to 25:00. It saved my ass.

[RyanCarmellini]

Great lecture. Very clearly explained alpha beta pruning. I liked the greater than and less than comparisons on each level. This was much clearer then just defining alpha and beta at each level.

[Apollys]

Wowwww I've never seen anyone evaluate the time cost of brute forcing chess the way he did! Amazing! This guy is just amazing.

[cameronmoore]

Came here for a good explanation of alpha-beta pruning, and got what I came for. Fantastic lecture!

...but what really blew me away was how *absurdly clean* that blackboard is. Just look at it!

[moosesnWoop]

Love these lectures - think about them throughout my day. Well seasoned Lecture. Sad to hear about his passing.

[avinkon]

Patrick Winston has a great teaching style with a subtle humor , childlike playfulness, enthusiasm, energetic and engaging lecture, enjoyed thoroughly :)

[adityavardhanjain]

This lecture is so good. It clears the concept on a theoretical and practical aspects both.

[ishratrhidita]

He is an amazing professor. I would have considered myself lucky to be in his class.

[EtzEchad]

The game tree depth is just one factor. I bigger problem is the evaluation of the board at each level. That is what makes current chess engines winners.

[GoogleUser-eero]

Prof Winston is quite a genius in giving funny Memorable names for algorithms - British Museum, dead horse, Marshall Art etc. Also the way he explained how Deep Blue applied minimax + alphabet prune + Progressive Deepening etc immediate relate the material to real-life applications. Good Job! But I hope he could explain more on how paralleled computing helped alpha beta punning in DB.

[insidioso]

Greetings from the Politecnico di Milano; thank you for these beautiful lectures!

[EchoVidsu]

30:29 Shouldn't the root then be = 8 ?